JP2010156373A - Split-type sliding bearing for crankshaft in internal combustion engine and split-type sliding bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein a step is created on a bearing inner circumferential surface of an abutting end face of a pair of semi-cylindrical bearing bodies, when the semi-cylindrical bearing bodies which are sliding bearings, are fitted to a pair of housing halves having a rigidity difference therebetween. <P>SOLUTION: The semi-cylindrical bearing body 20 supported by the low rigidity side housing half 14 and the semi-cylindrical bearing body 22 supported by the high rigidity side housing half 16 have an equal outer diameter in an initial condition. The wall thickness in both circumferential end areas of the semi-cylindrical bearing body 20 supported by the housing half 14 is larger than that in both circumferential end areas of the semi-cylindrical bearing body 22 supported by the housing half 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a split-type slide bearing for a crankshaft of an internal combustion engine that is used as a cylindrical body by combining a pair of bearing semi-cylindrical bodies with each other, and a cylindrical bearing that is divided into two in a manner consistent with the combined state The present invention relates to the above-described split type slide bearing that is used by being housed in a split type bearing housing having a holding hole and including a pair of housing split bodies (for example, see Patent Document 1).

A split type plain bearing for a crankshaft of an internal combustion engine becomes a cylindrical body by assembling a pair of bearing semi-cylindrical bodies into a housing divided body that is a part of an engine block and a housing divided body as a bearing cap. The bearing holding hole of the split bearing housing is processed in a single operation so as to be a perfect circle with the pair of housing split bodies fastened with bolts before the pair of bearing semi-cylindrical bodies are assembled.
Further, in recent years, in an internal combustion engine for a passenger car, an aluminum alloy engine block is generally used to reduce the weight of the internal combustion engine. In this case, in the split-type bearing housing for crankshaft, a combination in which one housing divided body is a part of an aluminum alloy engine block and the other housing divided body is an iron alloy bearing cap is common.

  On the other hand, the bearing semi-cylindrical body of the split type plain bearing for crankshaft is usually composed of a steel back metal and a bearing alloy layer. The outer peripheral surface circumference of the crankshaft split-type slide bearing formed of a pair of bearing semi-cylindrical bodies is formed to be larger than the inner peripheral surface peripheral length of the split-type bearing housing by a predetermined length. Due to this dimensional relationship, when the pair of bearing semi-cylindrical bodies are assembled to the split bearing housing, the pair of bearing semi-cylindrical bodies generate a radial direction stress as well as a circumferential compressive stress. As a result, the pair of bearing semi-cylindrical bodies are tightly fixed to the inner peripheral surface of the split bearing housing, and the split bearing housing is elastically deformed and expands in the radial direction to increase its inner diameter.

A bearing clearance for supplying lubricating oil is provided between the inner peripheral surface of the crankshaft split-type slide bearing composed of a pair of bearing semi-cylindrical bodies and the crankshaft. If this bearing clearance is excessive, backlash occurs on the crankshaft, causing vibration and noise in the internal combustion engine.
On the other hand, the inner diameter of the bearing holding hole in the split bearing housing and the outer diameter of the crankshaft are accompanied by processing errors at the time of manufacture, so that the gap between the split bearing housing and the crankshaft varies. Therefore, in order to properly set the bearing clearance between the inner peripheral surface of the split slide bearing and the crankshaft, by selecting a split slide bearing having an appropriate thickness, it is possible to suppress variations in the bearing clearance. There must be.

However, as described above, when the split slide bearing is assembled to the split bearing housing, the split bearing housing inner diameter expands and deforms in the radial direction. The bearing clearance when such expansion deformation occurs is compared with the designed bearing clearance determined by the inner diameter of the bearing holding hole in the split bearing housing, the outer diameter of the crankshaft, and the thickness of the bearing semi-cylindrical body. It increases by the amount of expansion deformation of the split bearing housing, and variation also occurs due to such expansion deformation.
This variation is taught in Patent Document 2 (Japanese Patent Laid-Open No. 10-175131), and is divided by a selective combination of the outer peripheral surface circumference of the split slide bearing and the inner diameter of the bearing holding hole of the split bearing housing. The variation in the distance between the split bearing housing and the crankshaft due to the expansion deformation of the bearing housing is reduced to reduce the variation in the bearing clearance.
JP-A-8-210355 JP-A-10-175131

In order to reduce the weight of the internal combustion engine, the crankshaft split-type bearing housing has been made more rigid than before. The use of a widely used aluminum alloy engine block is also for weight reduction.
Here, the relationship between the split-type bearing housing and the split-type slide bearing for crankshaft composed of a pair of bearing semi-cylindrical bodies incorporated therein will be described with reference to FIGS.
FIG. 9 shows a split-type bearing housing for crankshaft 01. The bearing housing 01 is divided into one housing divided body 02 which is a part of the engine block and the other housing divided as a bearing cap (for example, made of iron alloy). The body 03 is formed. In a state where the housing divided body 03 is assembled to the housing divided body 02 with bolts 04, a bearing holding hole (05, 06) having a perfectly circular cross section is formed by machining at room temperature. In the subsequent assembly of the bearing device, the bolts 04 are removed from the bearing housing 01, and the bearing semi-cylindrical bodies 07 and 08 forming the split slide bearings are mounted along the inner peripheral surfaces 05 and 06 of the bearing holding holes. The housing division body 03 is again fastened to the housing division body 02 with the bolts 04 (see FIG. 10).

  However, in order to tightly fit and fix the split-type slide bearing to the split-type bearing housing 01 with low rigidity that has been widely used in recent years, the bolt 04 is used so that the same level of stress is generated in the split-type slide bearing. When tightening, the amount of expansion and deformation of the inner diameter of the split bearing housing increases. Furthermore, since the housing divided bodies 02 and 03 constituting the split bearing housing have different rigidity, the abutting end surfaces of the housing split bodies 02 and 03 (the split surfaces of the split bearing housing) are caused by the stress that fixes the split slide bearing. ) In the inner diameters 05 and 06 in FIG. 10), which appears as a step (see symbol G in FIG. 10), and at the abutting end surfaces of the bearing semi-cylindrical bodies 07 and 08, a step ( g) occurs.

  On the other hand, in recent internal combustion engines, the amount of lubricating oil supplied to the inner peripheral surface of the crankshaft slide bearing has decreased due to the downsizing of the oil pump. Correspondingly, the bearing clearance is set smaller in order to reduce the amount of lubricating oil leakage from the bearing clearance between the inner peripheral surface of the crankshaft slide bearing and the crankshaft surface. Therefore, when the step (g) is formed on the bearing inner peripheral surface at the end face of the bearing semi-cylindrical bodies 07 and 08, the flow passage cross-sectional area of the lubricating oil is larger than when the conventional bearing clearance is set large. The ratio of the step area that becomes a barrier to the lubricating oil flow with respect to the oil becomes relatively high, the wiping phenomenon of the lubricating oil due to the step (g) occurs, the amount of lubricating oil leakage increases, and the lubricating oil supply to the bearing sliding surface Defects are starting to occur.

  Patent Document 2 teaches a means for reducing the bearing clearance between the inner peripheral surface of the plain bearing and the shaft surface for quietness of the internal combustion engine. No consideration has been given to the problem that a step is generated on the inner peripheral surface of the bearing at the abutting end face of the bearing semi-cylindrical body when the pair of bearing semi-cylindrical bodies are assembled to the pair of housing divided bodies.

  Thus, an object of the present invention is that when a pair of bearing semi-cylindrical bodies which are slide bearings are mounted on a pair of housing divided bodies which form a split bearing housing for a crankshaft of an internal combustion engine and which have a difference in rigidity, This is to solve the problem that a wiping phenomenon of the lubricating oil occurs due to a step formed on the inner peripheral surface of the bearing at the abutting end surface of the bearing semi-cylindrical body.

In light of this object, according to a first aspect of the present invention, there is provided the following split shaft bearing for a crankshaft of an internal combustion engine.
A split-type slide bearing for a crankshaft of an internal combustion engine that is used as a cylindrical body by combining a pair of bearing semi-cylindrical bodies with a cylindrical bearing holding hole that is divided into two in a manner that matches the combined state In the split slide bearing used by being housed in a split bearing housing,
The split bearing housing comprises a relatively low-rigidity housing split and a relatively high-rigidity housing split,
The bearing semi-cylindrical body supported by the low-rigidity side housing divided body is referred to as a first bearing semi-cylindrical body, and the bearing semi-cylindrical body supported by the high-rigidity side housing divided body is referred to as a second bearing semi-cylindrical body. When called, the dimensional relationship between the first and second bearing semi-cylindrical bodies in the non-mounted state is
(1) The outer diameters of the first and second bearing semi-cylindrical bodies are equal, and (2) the thicknesses of both ends in the circumferential direction of the first bearing semi-cylindrical body are the circumference of the second bearing semi-cylindrical body. It is made larger than the thickness at both ends in the direction,
Thereby, when the pair of housing divided bodies are bolted in a state where the first and second bearing semi-cylindrical bodies are incorporated, the butt end surfaces of the pair of housing divided bodies are based on the difference in rigidity. The inner peripheral surfaces of the two bearing semi-cylindrical bodies at the abutting end surfaces of the first and second bearing semi-cylindrical bodies are in an aligned state even if a step due to the difference in deformation between the two housing divided bodies occurs. A split slide bearing for a crankshaft of an internal combustion engine.
Here, the “alignment state of the inner peripheral surface” will be described.
This alignment does not mean geometrical coincidence between the peripheral surfaces of the bearing semi-cylindrical bodies, and both housings when the pair of housing divided bodies are bolted together with the first and second bearing semi-cylindrical bodies mounted. The difference in expansion deformation of the inner diameter of the bearing holding hole at the butt end surface of the divided body is obtained by, for example, the following “expansion deformation amount difference calculation formula”, and the value of ½ of this value is the bearing thickness at the butt end. This difference is set to allow an error determined by the processing accuracy in manufacturing the split slide bearing and split bearing housing.

(Equation 1)
ΔD = ΔD (L) −ΔD (H) Equation 1

Explanation of symbols:
ΔD: Expansion deformation difference (mm)
ΔD (L): Bearing holding hole inner diameter expansion deformation amount of low rigidity side split type bearing housing (mm)
ΔD (H): Bearing holding hole inner diameter expansion deformation of high rigidity side split type bearing housing (mm)

記号の説明：
Ｂ_Ｂ：組合せ円筒での軸受半円筒体剛性に関する係数(ｍｍ^２/Ｎ)
Ｂ_Ｈ(Ｌ)：組合せ円筒での低剛性側分割型軸受ハウジング剛性に関する係数(ｍｍ^２/Ｎ)
σ：締め代(軸受半円筒体外径−軸受保持穴内径)(ｍｍ)

Explanation of symbols:
B _B : Coefficient of bearing semi-cylindrical rigidity in combination cylinder (mm ² / N)
B _H (L): Coefficient of low rigidity side split type bearing housing in combination cylinder (mm ² / N)
σ: Tightening margin (Bearing semi-cylindrical outer diameter-Bearing holding hole inner diameter) (mm)

記号の説明：
ｔ：軸受半円筒体厚さ(ｍｍ)
Ｄ：軸受保持穴内径(ｍｍ)
Ｅ_Ｂ：軸受半円筒体のヤング率(ＧＰａ)
ν_Ｂ：軸受半円筒体のポアソン比

Explanation of symbols:
t: Bearing semi-cylinder thickness (mm)
D: Bearing holding hole inner diameter (mm)
E _B : Young's modulus (GPa) of bearing semi-cylindrical body
ν _B : Poisson's ratio of bearing semi-cylindrical body

記号の説明：
ν_Ｈ(Ｌ)：低剛性側分割型軸受ハウジングのポアソン比
Ｄ_Ｈ(Ｌ)：低剛性側分割型軸受ハウジングの外径(ｍｍ)
Ｅ_Ｈ(Ｌ)：低剛性側分割型軸受ハウジングのヤング率(ＧＰａ)

Explanation of symbols:
ν _H (L): Poisson's ratio of low rigidity side split bearing housing _DH (L): Outer diameter of low rigidity side split bearing housing (mm)
E _H (L): Young's modulus (GPa) of low rigidity side split type bearing housing

記号の説明：
Ｂ_Ｈ(Ｈ)：組合せ円筒での高剛性側分割型軸受ハウジング剛性に関する係数(ｍｍ^２/Ｎ)

Explanation of symbols:
B _H (H): Coefficient for high rigidity side split type bearing housing rigidity in combination cylinder (mm ² / N)

記号の説明：
ν_Ｈ(Ｈ)：高剛性側分割型軸受ハウジングのポアソン比
Ｄ_Ｈ(Ｈ)：高剛性側分割型軸受ハウジングの外径(ｍｍ)
Ｅ_Ｈ(Ｈ)：高剛性側分割型軸受ハウジングのヤング率(ＧＰａ)

Explanation of symbols:
ν _H (H): Poisson's ratio of high rigidity side split bearing housing _DH (H): Outer diameter of high rigidity side split bearing housing (mm)
E _H (H): Young's modulus (GPa) of high rigidity side split type bearing housing

According to the first embodiment of the sliding bearing of the present invention, the thickness of the first bearing semi-cylindrical body is made uniform over the entire circumferential length.
According to the second embodiment of the sliding bearing of the present invention, the thickness of the first bearing semi-cylindrical body increases from the central portion of the circumferential length toward both butted end faces.
According to the third embodiment of the sliding bearing of the present invention, the thickness of the second bearing semi-cylindrical body is uniform over the entire circumferential length.
According to the fourth embodiment of the sliding bearing of the present invention, the thickness of the second bearing semi-cylindrical body is reduced from the central portion of the circumferential length toward both butted end faces.
According to the fifth embodiment of the sliding bearing of the present invention, there are a large number of circumferential grooves extending in the circumferential direction at least on the inner peripheral surface of the second bearing semicylindrical body, and the second bearing semicylindrical body. The depth of the circumferential groove formed in the circumferential end region of the second bearing semi-cylindrical body including the two circumferential end surfaces is 5 μm or more and 20 μm or less.
According to the sixth embodiment of the sliding bearing of the present invention, there are a large number of circumferential grooves extending in the circumferential direction on the inner circumferential surface of the first bearing semi-cylindrical body, The depth of the circumferential groove formed in the circumferential end region of the first bearing semi-cylindrical body including the two circumferential end faces is set to 5 μm or more and 20 μm or less.
According to the seventh embodiment of the sliding bearing of the present invention, the circumferential end region of the inner circumferential surface of the first bearing semi-cylindrical body has at least a circumferential angle of 10 ° starting from the circumferential end surface, This is a range defined by a circumferential length corresponding to a circumferential angle of 50 ° at the maximum.
According to the eighth embodiment of the sliding bearing of the present invention, the surface roughness of the inner peripheral surface outside the range defined by the circumferential length in the first bearing semi-cylindrical body is 3.2 μmRz or less. .
According to the ninth embodiment of the sliding bearing of the present invention, the pitch of the circumferential groove in the first bearing semi-cylindrical body is 0.3 mm to 1.5 mm.
According to the tenth embodiment of the sliding bearing of the present invention, the depth of the circumferential groove formed on the inner peripheral surface of the second bearing semi-cylindrical body is determined by the butt of the first and second bearing semi-cylindrical bodies. The size is equal to or greater than the amount of step generated between the end faces.

According to the second aspect of the present invention, there is provided the following split shaft bearing device for a crankshaft of an internal combustion engine.
A split slide bearing for a crankshaft of an internal combustion engine, which is used as a cylindrical body by combining a pair of bearing semi-cylindrical bodies,
An internal combustion engine having a cylindrical bearing holding hole that is divided into two in a manner that matches the combined state of the pair of bearing semi-cylindrical bodies and that houses and holds the pair of bearing semi-cylindrical bodies in the bearing holding holes. In a split slide bearing device including a split bearing housing for a crankshaft,
The split bearing housing comprises a relatively low-rigidity housing split and a relatively high-rigidity housing split,
The bearing semi-cylindrical body supported by the low-rigidity side housing divided body is referred to as a first bearing semi-cylindrical body, and the bearing semi-cylindrical body supported by the high-rigidity side housing divided body is referred to as a second bearing semi-cylindrical body. When called, the dimensional relationship between the first and second bearing semi-cylindrical bodies in the non-mounted state is
(1) The outer diameters of the first and second bearing semi-cylindrical bodies are equal, and (2) the thicknesses of both ends in the circumferential direction of the first bearing semi-cylindrical body are the circumference of the second bearing semi-cylindrical body. It is made larger than the thickness at both ends in the direction,
Thereby, when the pair of housing divided bodies are bolted in a state where the first and second bearing semi-cylindrical bodies are incorporated, the butt end surfaces of the pair of housing divided bodies are based on the difference in rigidity. The inner peripheral surfaces of the two bearing semi-cylindrical bodies at the abutting end surfaces of the first and second bearing semi-cylindrical bodies are in an aligned state even if a step due to the difference in deformation between the two housing divided bodies occurs. A split-type plain bearing device for a crankshaft of an internal combustion engine.

[The invention's effect]
A split-type bearing housing for a crankshaft of an internal combustion engine comprises a pair of housing split bodies having a difference in rigidity from each other. According to the split-type slide bearing used by being mounted on the bearing housing, the split-type slide bearing is mounted. Bearings on the butted end surfaces of the pair of housing split bodies (split surfaces of the split bearing housing) due to the stress of fixing the split slide bearings when the pair of housing split bodies having different rigidity are fastened with bolts There is a difference in the amount of expansion deformation between the low-rigidity housing divided body and the high-rigidity housing divided body on the inner diameter of the holding hole, and this appears as a step (see symbol G in FIG. 10). Unlike a bearing, there is virtually no step on the end face of the pair of bearing semi-cylindrical bodies held in the bearing holding hole. This is because the thickness of the abutting end of the bearing semi-cylindrical body mounted along the low-rigidity housing segment having a large expansion deformation amount is equal to that of the bearing half cylinder mounted along the high-rigidity housing segment having a small expansion deformation amount. This is because the thickness is made larger than the thickness of the butted end portion of the cylindrical body, and by appropriately selecting the difference in thickness, the step generated on the butted end surfaces of the pair of housing divided bodies can be virtually offset.

FIG. 1 is a front view showing a state in which a split type slide bearing comprising a pair of bearing semi-cylindrical bodies 20 and 22 is mounted in a bearing holding hole 12 of a split type bearing housing 10 for a crankshaft of an internal combustion engine. The split bearing housing 10 is formed of a low-rigidity side housing divided body 14 that forms a part of an aluminum alloy engine block, and a high-rigidity side housing divided body 16 as an iron alloy bearing cap. , 16 are integrally fastened by bolts 18. The bearing holding hole 12 of the split bearing housing 10 is machined into a cylindrical hole having a true circular cross section in a state where the housing split bodies 14 and 16 are assembled using bolts 18 without mounting the split slide bearing. Formed. The split bearing housing 10 after the bearing holding hole 12 is formed by machining as described above is disassembled, and the bearing semi-cylindrical bodies 20 and 22 are mounted along the inner peripheral surfaces of the housing divided bodies 14 and 16. Again, FIG. 1 shows a state in which the housing divided bodies 14 and 16 are integrally combined with the bolts 18.
The bearing semi-cylindrical bodies 20 and 22 are in the initial state before being incorporated into the split bearing housing 10, but have the same outer diameter, but the wall thicknesses of the butted ends 20 a and 22 a are different. That is, the wall thickness relationship is such that the wall thickness of the butted end portion 20a is larger than the wall thickness of the butted end portion 22a. The wall thickness of the bearing semi-cylindrical bodies 20 and 22 is the largest at the circumferential center portions 20x and 22x of the bearing semi-cylindrical bodies, and gradually decreases toward the butt end faces 20b and 22b.

  However, when the housing divided bodies 14 and 16 are integrally combined with the bolts 18, as described in the above [0007] column and as shown in FIG. Is larger than the amount of expansion deformation at the abutting end portion of the high-rigidity side housing divided body 16, the inner diameter of the bearing holding hole 12 is different between the two housing divided bodies 14, 16. A step (g) as shown in FIG. 10 may occur between the butted end surfaces 20b and 22b of the bodies 20 and 22. FIG. However, in the present embodiment, the outer diameters of the bearing semi-cylindrical bodies 20 and 22 in the initial state are equal, and the wall thickness of the butted end portion 20a is larger than the wall thickness of the butted end portion 22a. The end surfaces 20b and 22b are designed so that the inner peripheral surfaces of the two bearing semi-cylindrical bodies 20 and 22 are aligned with each other, resulting in a butt end surface 20b and 22b as shown in FIG. For this reason, the wiping phenomenon of the lubricating oil hardly occurs at the butted end surfaces 20b and 22b of the both bearing semi-cylindrical bodies 20 and 22.

Actually, in order to configure the inner peripheral surfaces of the two bearing semi-cylindrical bodies 20 and 22 to be aligned with each other as described above, the split bearing housing 10 (the cylinder block and the bearing cap) or the actual one is modeled. The model of the split bearing housing part created in this way is used.
A pair of bearing semi-cylindrical bodies of the same shape and the same dimensions are mounted in the bearing holding holes of the split bearing housing, and the bearing semi-cylindrical bodies are fastened with bolts. The step size of the inner diameter is measured using a measuring machine such as a roundness measuring machine.
Using this measured value, the wall thickness at both ends in the circumferential direction of the bearing semi-cylindrical body to be attached to the relatively low-rigidity housing division is attached to the relatively high-rigidity housing division. It is good to make it larger by the step size value actually measured using the real thing or the model than the wall thickness of the circumferential direction both ends of the power bearing semi-cylindrical body.

  Alternatively, the rigidity is relatively low by a value that is ½ of the difference in expansion deformation of the inner diameter of the bearing holding hole of the split bearing housing, which is simply obtained by the mathematical formulas described in the columns [0012] to [0017]. The wall thickness of both ends in the circumferential direction of the bearing semi-cylindrical body to be mounted on the housing division on the side is set to be equal to that of the circumferential end of the bearing semi-cylindrical body to be mounted on the relatively rigid housing division. It may be larger than the wall thickness.

  In the [0016] column, it was stated that “the inner peripheral surfaces of the bearing semi-cylindrical bodies 20 and 22 are aligned with each other at the butted end surfaces 20b and 22b”. This “alignment” is geometrically perfect. It is not limited to just a consistent state. This is because when manufacturing the double-bearing semi-cylindrical body and when machining the bearing holding hole of the split-type bearing housing, a processing error occurs, and further, the double-bearing semi-cylindrical body is attached to the split-type bearing housing, This is because even when the split bearing housing is refastened with bolts, the butt end faces 20b and 22b are slightly misaligned. For this reason, a step within 5 μm (that is, within ± 5 μm) in the radial direction is allowed on one abutting side of both bearing semi-cylindrical bodies.

  In this embodiment, the thickness (20x, 22x) of the center portion in the circumferential direction of both bearing semi-cylindrical bodies, which is the most common as a split slide bearing for an internal combustion engine, is the largest and thicker toward both end surfaces in the circumferential direction. Although the present invention has been described using a specification that decreases, the present invention is not limited to this specification. In the present invention, when a pair of bearing semi-cylindrical bodies are mounted on a split bearing housing, the thickness of both bearing semi-cylindrical bodies is set to the circumferential direction as long as the inner peripheral surfaces are aligned at both circumferential end faces of both bearing semi-cylindrical bodies. Specifications that are the same throughout, specifications that the thickness of the center part in the circumferential direction of both bearing semi-cylindrical bodies is the smallest and the thickness increases toward both end faces in the circumferential direction, or the inner peripheral surfaces of both bearing semi-cylindrical bodies are curved The specifications formed by a plurality of arcuate surfaces differing from each other may be used, or a pair of bearing semi-cylindrical bodies having different specifications may be used in combination.

  Further, as in the conventional bearing semi-cylindrical body, crush reliefs (20c, 22c: inner diameter enlarged portions) may be formed at both ends in the circumferential direction on the inner peripheral surface side of the bearing semi-cylindrical bodies 20A, 22A (see FIG. 2). ). When forming a crush relief, the bearing center at the circumferential surface position in the bearing semi-cylinder body directly adjacent to the crush relief forming area of the two-bearing semi-cylindrical body mounted on the low-rigidity side housing division and the high-rigidity side housing division The radial dimensions (r1, r2) from the second line should be matched (FIG. 2: r1 = r2).

  This will be described with reference to FIG. In the present embodiment, the same split bearing housing 10 as that of the first embodiment is used, and a bearing semi-cylindrical body 20B having a uniform wall thickness in the circumferential direction is mounted on the low rigidity side housing divided body 14 made of aluminum alloy. The semi-cylindrical bearing body 16 has the largest wall thickness in the central portion in the circumferential direction and the thickness decreases toward the butt end face 22b (the latter is the bearing semi-cylindrical shown in FIG. 1). When the housing divided bodies 14 and 16 are fastened with bolts, the inner peripheral surfaces of the pair of bearing semi-cylindrical bodies 20B and 22 are aligned with each other in the circumferential direction. 3 shows. According to this configuration, the clearance between the inner peripheral surface of the bearing semi-cylindrical body 20B mounted on the low-rigidity side housing divided body 14 having a large expansion deformation amount and the supported shaft (not shown) is reduced. Since it can be made small over the entire inner peripheral surface of the body 20B, it is effective for preventing leakage of the lubricating oil. In this case, the bearing semi-cylindrical body 22 incorporated in the high-rigidity side housing divided body 16 is not limited in shape as long as the inner peripheral surface is aligned at the abutting end face, but it is most quiet in operating the internal combustion engine. The thickness of the circumferential center of the bearing semi-cylindrical body is the largest and the thickness decreases toward both circumferential end faces (butting end faces) so that the bearing clearance at the circumferential center of the affected sliding bearing is reduced. It is preferable to use the bearing semi-cylindrical body 22.

This will be described with reference to FIG. The split bearing housing 10 composed of a pair of housing split bodies 14 and 16 is fastened with bolts 18. The inner diameter of the housing split body 14 at the abutting end surface of the low-rigidity side housing split body 14 is due to the stress at the time of bolt fastening. There is a case where it expands and elastically deforms so that the inner diameter of the housing divided body is small in the direction perpendicular to the virtual plane including both butted end faces. In this case, if a bearing semi-cylindrical body having a normal uniform wall thickness is used, a bearing between the inner diameter of the bearing semi-cylindrical body mounted on the low-rigidity side housing divided body 14 and the crankshaft as the supported shaft is used. The clearance gradually increases toward the circumferential end surface of the bearing semi-cylindrical body, and the amount of lubricating oil leaking from the enlarged portion of the bearing clearance increases. As a countermeasure, in the present embodiment, the wall thickness is increased from the circumferential central portion of the bearing semi-cylindrical body 20C attached to the low-rigidity side housing divided body 14 toward the circumferential end surface. As a result, even in the circumferential end portion of the bearing semi-cylindrical body 20C, it is possible to keep the bearing clearance small and keep it small.
The bearing semi-cylindrical body 22B mounted on the high-rigidity side housing divided body 16 has a uniform wall thickness over the entire length in the circumferential direction. The wall thickness of the bearing semi-cylindrical body 22B is smaller than the wall thickness of the circumferential end portion of the bearing semi-cylindrical body 20C.
The specifications of the bearing semi-cylindrical body mounted on the high-rigidity side housing divided body 16 are not particularly limited as long as the inner peripheral surface of the butt end surface is aligned with the inner peripheral surface of the butt end surface of the bearing semi-cylindrical body 20C. In order to reduce the bearing clearance as much as possible over the entire circumferential length of the bearing semi-cylindrical body 22B and to improve the quietness during operation of the internal combustion engine, a wall is formed over the entire circumferential length of the bearing semi-cylindrical body. It is preferable to use a bearing semi-cylindrical body 22B having a uniform thickness (see FIG. 4).

  This will be described with reference to FIG. In this embodiment, the bearing semi-cylindrical body 20D mounted on the low-rigidity aluminum alloy housing divided body 14 is used in contrast to the bearing semi-cylindrical body 22C mounted on the relatively high-rigidity iron alloy housing divided body 16. The thickness of both end portions in the circumferential direction is increased to align the inner peripheral surfaces of the butted surfaces of the pair of bearing semi-cylindrical bodies 20D and 22C. However, when the bearing semi-cylindrical bodies 20D and 22C are manufactured and when the bearing holding hole 12 of the split housing 10 formed of the housing split bodies 14 and 16 is machined, a machining error occurs, and the split bearing housing has a problem. Even when the bearing semi-cylindrical bodies 20D and 22C are mounted and the housing divided bodies 14 and 16 are fastened by the bolts 18, a slight misalignment of the abutting surfaces of the housing divided bodies 14 and 16 (divided surfaces of the divided housings) occurs. Therefore, there may be a step (g) of about 5 μm at the maximum in the radial direction at the butt end face on one side of the pair of bearing semi-cylindrical bodies 20D and 22C.

  FIG. 5 shows that when the housing divided bodies 14 and 16 are fastened with bolts, misalignment occurs at the abutting surfaces of the housing divided bodies 14 and 16 (divided surfaces of the divided housings), and the bearing semi-cylindrical bodies 20D and 22C are abutted. A state where a step (g) is generated on the inner peripheral surface at the end surface is shown. FIG. 7 shows an enlarged view of the step forming portion A of the bearing semi-cylindrical bodies 20D and 22C in FIG. In FIG. 7, the crankshaft 30 is shown.

  The bearing semi-cylindrical bodies 20D and 22C are the same as the specifications of the bearing semi-cylindrical bodies 20B and 22 in the third embodiment (see FIG. 3) except that a large number of circumferential grooves 20d and 22d are formed on the inner circumferential surface. The same. The preferable groove shape of the circumferential grooves 20d and 22d is an arc shape in cross section as shown in FIG. In the figure, H indicates the depth of the circumferential grooves 20d and 22d. When the step (g) which is a part of the butted end face of the bearing semi-cylindrical body 20C is viewed in the direction indicated by the arrow B in FIG. 7, the cross-sectional shape of the circumferential groove 20d shown in FIG. Appears in the open state.

  Even if a step (g) of about 5 μm at the maximum is formed on the bearing inner peripheral surface at the abutting end surfaces of the bearing semi-cylindrical bodies 20D and 22C, the inner circumferential surface of the circumferential grooves 20d and 22d is formed as in the present embodiment. If there is a circumferential groove of 5 μm or more and 20 μm or less, the depth of the circumferential groove is equal to or greater than the size of the step (g), so that the lubricating oil flows in the rotation direction of the crankshaft 30 (FIG. 7: arrow X). However, it enters into the circumferential groove 20d and smoothly flows without being hindered by the step (g) generated on the end face of the bearing semi-cylindrical body 20D. Therefore, the lubricating oil wiping phenomenon due to the step (g) can be successfully prevented.

  On the other hand, when the circumferential groove is not formed on the inner peripheral surface of the bearing semi-cylindrical body, a step generated on the end face of the bearing semi-cylindrical body is a course of the lubricating oil flowing in the rotation direction of the crankshaft. As a barrier, the wiping phenomenon of the lubricating oil due to the level difference occurs. As a result, the lubricating oil that has reached the position of the step easily flows along the step in the width direction of the bearing, and sufficient lubrication of the bearing is not guaranteed.

Previously, it was described that the groove depth (H) of the circumferential grooves 20d and 22d was 20 μm or less. The reason for the limitation is that if it exceeds 20 μm, it becomes difficult to form a lubricating oil film on the sliding surface at the center in the circumferential direction of the bearing semi-cylindrical body that is mainly subjected to a dynamic load during operation of the internal combustion engine. . A more preferable circumferential groove depth is 10 μm or more and 15 μm or less.
Moreover, the pitch in the bearing width direction of the circumferential groove formed on the inner peripheral surface of the bearing semi-cylindrical body is 0.3 mm or more and 1.5 mm or less. The reason is that if the pitch is less than 0.3 mm, the circumferential direction Each cross-sectional area of the apex of the crest forming the groove is excessively small, and wears easily due to contact with the crankshaft. When wear increases, bearing clearance increases and the amount of lubricating oil leakage increases. Because it becomes. If the circumferential groove pitch exceeds 1.5 mm, the bearing semi-cylindrical body that supports the load from the crankshaft has a small number of peaks in the bearing width direction, so the surface pressure received at one peak is high. As a result, the material strength of the bearing semi-cylindrical body decreases due to frictional heat, and the amount of wear increases. A more preferable circumferential groove pitch in the width direction of the bearing semi-cylindrical body for reducing the wear of the bearing semi-cylindrical body is 0.5 mm to 1.2 mm.

  The circumferential grooves 20d and 22d of the bearing semi-cylindrical bodies 20D and 22C are formed on the entire inner peripheral surface, but on the side where the step (g) facing the direction opposite to the rotation direction of the crankshaft exists. The bearing semi-cylindrical bodies 20D and 22C may be formed only in a circumferential length range corresponding to a predetermined circumferential angle starting from the circumferential end face.

In addition, although the suitable groove shape of the circumferential grooves 20d and 22d is a cross-sectional arc shape as shown in FIG. 8, a cross-sectional V-shape is also suitable.
When the groove shape of the circumferential groove is an arc shape in cross section, about 2/3 or more of the step surface which is a part of the abutting surface of the bearing semi-cylindrical body is the groove inner space, and the lubricating oil flows in the groove. This indicates that the same effect as that obtained when the step amount (g: FIG. 7) is substantially ３ or less can be obtained.
When the groove shape of the circumferential groove has a V-shaped cross section, about 1/2 or more of the step surface which is a part of the mating surface of the bearing semi-cylindrical body is the groove space, and the lubricating oil flows in the groove. . This indicates that the same effect as that obtained when the step amount (g: FIG. 7) is substantially reduced to ½ or less can be obtained.
In order to form the circumferential groove, a cutting blade having a circular arc shape or a V shape may be used, and the shape of the cutting blade tip may be transferred to the inner peripheral surface of the bearing semi-cylindrical body by turning.

Here, another example of the circumferential groove forming form shown in FIG. 6 will be described. The bearing semi-cylindrical bodies 20E and 22D shown in FIG. 6 have substantially the same specifications as the bearing semi-cylindrical bodies 20D and 22C shown in FIG. 5, but the formation range of the circumferential grooves 20e and 22e is different from the example shown in FIG. . That is, the circumferential grooves 20e and 22e are formed in a circumferential length range corresponding to at least a circumferential angle of 10 ° and a maximum circumferential angle of 50 ° starting from the circumferential end surfaces of the bearing semi-cylindrical bodies 20E and 22D. Has been. According to this configuration, as in the case of the fourth embodiment, even if a step is generated on the circumferential end surface of the bearing semi-cylindrical body, the wiping phenomenon of the lubricating oil can be effectively prevented.
Further, in the inner peripheral surface range in which the circumferential grooves 20e and 22e are not formed, the roughness is 3.2 μmRz or less, which is a normal roughness of a split slide bearing for a crankshaft. According to this surface roughness, an oil film is easily formed on the sliding surface in the central portion in the circumferential direction which is the main load portion of the bearing semi-cylindrical body, and sufficient load capacity as a sliding bearing is guaranteed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing a state in which a split shaft bearing for a crankshaft of an internal combustion engine according to a first embodiment of the present invention is mounted on a split bearing housing composed of bearing housings having a difference in rigidity. The same drawing as FIG. 1 which shows the state which provided the crush relief to the split-type slide bearing shown in FIG. The front view which shows the state which mounted | wore the split-type bearing housing which consists of a bearing housing with a mutually different rigidity in the split-type slide bearing for crankshafts of the internal combustion engine which concerns on Example 2 of this invention. The front view which shows the state which mounted | wore the split type bearing housing which consists of a bearing housing with a mutually different rigidity in the split type slide bearing for crankshafts of the internal combustion engine which concerns on Example 3 of this invention. The front view which shows the state which mounted | wore the split type bearing housing which consists of a bearing housing with a mutually different rigidity in the split type slide bearing for crankshafts of the internal combustion engine which concerns on Example 4 of this invention. The front view which shows the state which mounted | wore the split type bearing housing which consists of a bearing housing with a mutually different rigidity in the split type slide bearing for crankshafts of the internal combustion engine which concerns on Example 5 of this invention. The level | step difference formation part A in FIG. 5 is expanded and shown. The figure which looked at the cross-sectional shape of the circumferential groove | channel formed in the internal peripheral surface of the bearing semi-cylindrical body which comprises the split-type slide bearing shown in Example 4 in the circumferential direction end surface of the bearing semi-cylindrical body. Explanatory drawing of the prior art example which shows the split-type bearing housing which consists of a pair of bearing housing from which rigidity differs mutually in an assembly state. FIG. 10 is an explanatory diagram of a conventional example showing a state in which a split slide bearing including a pair of bearing semi-cylindrical bodies is assembled to the split bearing housing shown in FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Split type bearing housing for crankshafts of internal combustion engine 12 Bearing holding hole 14 Low rigidity side housing divided body 16 High rigidity side housing divided body 18 Bolt 20 Bearing semi-cylindrical body 20A Bearing semi-cylindrical body 20B Bearing semi-cylindrical body 20C Bearing semi-cylindrical body Body 20D bearing semi-cylindrical body 20E bearing semi-cylindrical body 20a butt end 20b butt end surface 20c crash relief 20d circumferential groove 20e circumferential groove 22 bearing semi-cylindrical body 22A bearing semi-cylindrical body 22B bearing semi-cylindrical body 22C bearing semi-cylindrical body Body 22D Bearing semi-cylindrical body 22a Butt end 22b Butt end surface 22c Crash relief 22d Circumferential groove 22e Circumferential groove 30 Crankshaft

Claims (28)

A split-type slide bearing for a crankshaft of an internal combustion engine that is used as a cylindrical body by combining a pair of bearing semi-cylindrical bodies with a cylindrical bearing holding hole that is divided into two in a manner that matches the combined state In the split slide bearing used by being housed in a split bearing housing,
The split bearing housing comprises a relatively low-rigidity housing split and a relatively high-rigidity housing split,
The bearing semi-cylindrical body supported by the low-rigidity side housing divided body is referred to as a first bearing semi-cylindrical body, and the bearing semi-cylindrical body supported by the high-rigidity side housing divided body is referred to as a second bearing semi-cylindrical body. When called, the dimensional relationship between the first and second bearing semi-cylindrical bodies in the non-mounted state is
(1) The outer diameters of the first and second bearing semi-cylindrical bodies are equal, and (2) the thicknesses of both ends in the circumferential direction of the first bearing semi-cylindrical body are the circumference of the second bearing semi-cylindrical body. It is made larger than the thickness at both ends in the direction,
Thereby, when the pair of housing divided bodies are bolted in a state where the first and second bearing semi-cylindrical bodies are incorporated, the butt end surfaces of the pair of housing divided bodies are based on the difference in rigidity. The inner peripheral surfaces of the two bearing semi-cylindrical bodies at the abutting end surfaces of the first and second bearing semi-cylindrical bodies are in an aligned state even if a step due to the difference in deformation between the two housing divided bodies occurs. A split slide bearing for a crankshaft of an internal combustion engine.   2. The split slide bearing for a crankshaft of an internal combustion engine according to claim 1, wherein the thickness of the first bearing semi-cylindrical body is uniform over the entire length in the circumferential direction.   2. The split for a crankshaft of an internal combustion engine according to claim 1, wherein the thickness of the first bearing semi-cylindrical body increases from the central portion of the circumferential length toward both butted end faces. Type slide bearing.   The internal combustion engine according to any one of claims 1 to 3, wherein the second bearing semi-cylindrical body has a uniform thickness over the entire length in the circumferential direction. Split type plain bearing for crankshaft.   The thickness of the second bearing semi-cylindrical body is reduced from the central portion of the circumferential length toward both butted end faces, according to any one of claims 1 to 3. A split slide bearing for a crankshaft of an internal combustion engine as described.   The second bearing semi-cylinder includes a plurality of circumferential grooves extending in the circumferential direction at least on the inner circumferential surface of the second bearing semi-cylindrical body, and includes two circumferential end surfaces of the second bearing semi-cylindrical body. 6. The internal combustion engine according to claim 1, wherein a depth of the circumferential groove formed in a circumferential end region of the body is 5 μm or more and 20 μm or less. Split bearing for engine crankshaft.   The circumferential end region on the inner circumferential surface is a range defined by a circumferential length starting from the circumferential end surface and having a circumferential angle corresponding to at least a circumferential angle of 10 ° and a maximum circumferential angle of 50 °. Item 7. A split slide bearing for a crankshaft of an internal combustion engine according to Item 6.   The split type plain bearing for a crankshaft of an internal combustion engine according to claim 7, wherein the surface roughness of the inner peripheral surface outside the range defined by the circumferential length is 3.2 µmRz or less.   The split slide bearing for a crankshaft of an internal combustion engine according to any one of claims 6 to 8, wherein a pitch of the circumferential groove is 0.3 mm to 1.5 mm.   The depth of the circumferential groove formed on the inner peripheral surface of the second bearing semi-cylindrical body is equal to or greater than the step amount generated between the butted end surfaces of the first and second bearing semi-cylindrical bodies. A split slide bearing for a crankshaft of an internal combustion engine according to any one of claims 6 to 9.   The first bearing semi-cylindrical body includes a plurality of circumferential grooves extending in the circumferential direction on the inner circumferential surface of the first bearing semi-cylindrical body and includes two circumferential end faces of the first bearing semi-cylindrical body. 7. A split type plain bearing for a crankshaft of an internal combustion engine according to claim 6, wherein the depth of the circumferential groove formed in the circumferential end region of the cylinder is 5 to 20 [mu] m.   The circumferential end region of the inner circumferential surface of the first bearing semi-cylindrical body has a circumferential length corresponding to at least a circumferential angle of 10 ° and a maximum circumferential angle of 50 ° starting from the circumferential end surface. The split slide bearing for a crankshaft of an internal combustion engine according to claim 11, which is in a range defined by   The division for a crankshaft of an internal combustion engine according to claim 12, wherein a surface roughness of the inner peripheral surface outside the range defined by the circumferential length in the first bearing semi-cylindrical body is 3.2 µmRz or less. Type slide bearing.   The split type for a crankshaft of an internal combustion engine according to any one of claims 11 to 13, wherein a pitch of the circumferential groove in the first bearing semi-cylindrical body is 0.3 mm to 1.5 mm. Slide bearing. A split slide bearing for a crankshaft of an internal combustion engine, which is used as a cylindrical body by combining a pair of bearing semi-cylindrical bodies,
An internal combustion engine having a cylindrical bearing holding hole that is divided into two in a manner that matches the combined state of the pair of bearing semi-cylindrical bodies and that houses and holds the pair of bearing semi-cylindrical bodies in the bearing holding holes. In a split slide bearing device including a split bearing housing for a crankshaft,
The split bearing housing comprises a relatively low-rigidity housing split and a relatively high-rigidity housing split,
The bearing semi-cylindrical body supported by the low-rigidity side housing divided body is referred to as a first bearing semi-cylindrical body, and the bearing semi-cylindrical body supported by the high-rigidity side housing divided body is referred to as a second bearing semi-cylindrical body. When called, the dimensional relationship between the first and second bearing semi-cylindrical bodies in the non-mounted state is
(1) The outer diameters of the first and second bearing semi-cylindrical bodies are equal, and (2) the thicknesses of both ends in the circumferential direction of the first bearing semi-cylindrical body are the circumference of the second bearing semi-cylindrical body. It is made larger than the thickness at both ends in the direction,
Thereby, when the pair of housing divided bodies are bolted in a state where the first and second bearing semi-cylindrical bodies are incorporated, the butt end surfaces of the pair of housing divided bodies are based on the difference in rigidity. The inner peripheral surfaces of the two bearing semi-cylindrical bodies at the abutting end surfaces of the first and second bearing semi-cylindrical bodies are in an aligned state even if a step due to the difference in deformation between the two housing divided bodies occurs. A split-type plain bearing device for a crankshaft of an internal combustion engine.   The split slide bearing device for a crankshaft of an internal combustion engine according to claim 15, wherein the thickness of the first bearing semi-cylindrical body is uniform over the entire length in the circumferential direction.   The division for a crankshaft of an internal combustion engine according to claim 15, wherein the thickness of the first bearing semi-cylindrical body increases from the central portion of the circumferential length toward both butted end faces. Type sliding bearing device.   The internal combustion engine according to any one of claims 15 to 17, wherein the second bearing semi-cylindrical body has a uniform thickness over the entire circumferential length. Split-type plain bearing device for crankshaft.   The thickness of the second bearing semi-cylindrical body is reduced from the central portion of the circumferential length toward both butted end faces, according to any one of claims 15 to 17. A split slide bearing device for a crankshaft of an internal combustion engine as described.   The second bearing semi-cylinder includes a plurality of circumferential grooves extending in the circumferential direction at least on the inner circumferential surface of the second bearing semi-cylindrical body, and includes two circumferential end surfaces of the second bearing semi-cylindrical body. 20. The internal combustion engine according to claim 15, wherein a depth of the circumferential groove formed in a circumferential end region of the body is 5 μm or more and 20 μm or less. Split slide bearing device for engine crankshaft.   The circumferential end region on the inner circumferential surface is a range defined by a circumferential length starting from the circumferential end surface and having a circumferential angle corresponding to at least a circumferential angle of 10 ° and a maximum circumferential angle of 50 °. Item 20. A split slide bearing device for a crankshaft of an internal combustion engine according to Item 20.   The split type plain bearing device for a crankshaft of an internal combustion engine according to claim 21, wherein the surface roughness of the inner peripheral surface outside the range defined by the circumferential length is 3.2 µmRz or less.   The split slide bearing device for a crankshaft of an internal combustion engine according to any one of claims 20 to 22, wherein a pitch of the circumferential grooves is 0.3 mm to 1.5 mm.   The depth of the circumferential groove formed on the inner peripheral surface of the second bearing semi-cylindrical body is equal to or greater than the step amount generated between the butted end surfaces of the first and second bearing semi-cylindrical bodies. 24. A split type plain bearing device for a crankshaft of an internal combustion engine according to any one of claims 20 to 23.   A plurality of circumferential grooves extending in the circumferential direction are present on the inner circumferential surface of the first bearing semi-cylindrical body, and the circumferential end portions on the inner circumferential surface of the first bearing semi-cylindrical body are in sliding contact with the supported shaft. 21. The split type plain bearing device for a crankshaft of an internal combustion engine according to claim 20, wherein the circumferential groove formed in the region has a depth of 5 to 20 [mu] m.   The circumferential end region of the inner circumferential surface of the first bearing semi-cylindrical body has a circumferential length corresponding to at least a circumferential angle of 10 ° and a maximum circumferential angle of 50 ° starting from the circumferential end surface. 26. The split type plain bearing device for a crankshaft of an internal combustion engine according to claim 25, which is in a range defined by.   27. A split for a crankshaft of an internal combustion engine according to claim 26, wherein a surface roughness of the inner peripheral surface of the first bearing semi-cylindrical body outside the range defined by the circumferential length is 3.2 μmRz or less. Type sliding bearing device.   The split type for a crankshaft of an internal combustion engine according to any one of claims 25 to 27, wherein a pitch of the circumferential groove in the first bearing semi-cylindrical body is 0.3 mm to 1.5 mm. Slide bearing device.

Images